Lighting devices with individually compensating multi-color clusters

Patent metadata

Field	Value
Publication number	US-10098197-B2
Application number	US-201113152772-A
Country	US
Kind code	B2
Filing date	Jun 3, 2011
Priority date	Jun 3, 2011
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

A lighting device includes multiple solid state emitter (e.g., LED) chips of different colors mounted on a single submount, at least one temperature sensing element arranged to sense temperature of the LED chips, and at least one temperature compensation circuit element mounted on the single submount to maintain output emissions at a substantially constant color point over a range of different temperatures. Such a device may include a blue LED arranged to stimulate a yellow lumiphor and a red LED, arranged in combination to yield warm white light. Multiple separately temperature compensated clusters of solid state emitters may be provided in a single lighting device, which may include an elongated body structure.

First claim

What is claimed is:

1. A light fixture or lighting apparatus comprising a plurality of lighting devices, wherein each lighting device of the plurality of lighting devices includes:
(i) a plurality of light emitting diode (LED) chips mounted on a submount, the plurality of LED chips including at least one first LED chip and at least one second LED chip, wherein spectral output of the at least one first LED chip includes a first peak wavelength, and spectral output of the at least one second LED chip includes a second peak wavelength that is substantially different from the first peak wavelength;
(ii) at least one thermal temperature sensing element configured to sense thermal temperature of at least one LED chip of the plurality of LED chips, wherein the lighting device is devoid of any light sensing element configured to sense light and generate a sensing element output signal used to adjust supply of current to the plurality of LED chips during operation of the lighting device; and
(iii) at least one thermal temperature compensation circuit element mounted on the submount, and configured to adjust supply of current to at least one LED chip of the plurality of LED chips responsive to an output signal of the at least one thermal temperature sensing element to maintain a color or color temperature of aggregate emissions of the plurality of LED chips;
wherein the light fixture or lighting apparatus includes at least one of the following features (a) to (e):
(a) each lighting device of the plurality of lighting devices is mounted to a common substrate of the light fixture or lighting apparatus;
(b) each lighting device of the plurality of lighting devices is in conductive thermal communication with a single heatsink of the light fixture or lighting apparatus;
(c) each lighting device of the plurality of lighting devices is configured to cause emissions to be reflected by a single reflector of the light fixture or lighting apparatus;
(d) each lighting device of the plurality of lighting devices is configured to cause emissions to be transmitted through a single lens of the light fixture or lighting apparatus; or
(e) each lighting device of the plurality of lighting devices is configured to cause emissions to be diffused by a single diffuser of the light fixture or lighting apparatus.

2. A light fixture or lighting apparatus according to claim 1 wherein, for each lighting device of the plurality of lighting devices, output emissions of the lighting device comprise spectral output of each LED chip of the plurality of LED chips, and the at least one thermal temperature compensation circuit element is configured to maintain the output emissions at a substantially constant color or color temperature over a range of different thermal temperatures sensed by the at least one thermal temperature sensing element spanning at least 15° C.

3. A light fixture or lighting apparatus according to claim 1 wherein, for each lighting device of the plurality of lighting devices, the submount comprises a printed circuit board.

4. A light fixture or lighting apparatus according to claim 1 wherein, for each lighting device of the plurality of lighting devices, the at least one thermal temperature compensation circuit element is adapted to increase current or current pulse width supplied to the at least one second LED chip, relative to current or current pulse width supplied to the at least one first LED chip, responsive to an increased thermal temperature sensed by the at least one thermal temperature sensing element.

5. A light fixture or lighting apparatus according to claim 1 wherein, for each lighting device of the plurality of lighting devices, the at least one thermal temperature compensation circuit element is adapted to adjust current pulse width to at least one LED chip of the plurality of LED chips.

6. A light fixture or lighting apparatus according to claim 1 wherein, for each lighting device of the plurality of lighting devices, the at least one thermal temperature compensation circuit element comprises at least one current bypass element or current shunt element.

7. A light fixture or lighting apparatus according to claim 1 wherein, for each lighting device of the plurality of lighting devices, the at least one thermal temperature compensation circuit element comprises a current mirror.

8. A light fixture or lighting apparatus according to claim 1 wherein, for each lighting device of the plurality of lighting devices, the at least one thermal temperature compensation circuit element comprises an operational amplifier.

9. A light fixture or lighting apparatus according to claim 1 wherein, for each lighting device of the plurality of lighting devices, the at least one thermal temperature compensation circuit element comprises a resistor network including at least one trimmed resistor.

10. A light fixture or lighting apparatus according to claim 1 wherein, for each lighting device of the plurality of lighting devices, the at least one thermal temperature compensation circuit element comprises an integrated circuit with an associated memory storing at least one value used to adjust supply of current to the at least one LED chip of the plurality of LED chips responsive to the output signal of the at least one thermal temperature sensing element.

11. A light fixture or lighting apparatus according to claim 1 wherein, for each lighting device of the plurality of lighting devices, the at least one thermal temperature compensation circuit element comprises a memory configured to store at least one value or instruction useable for adjusting supply of current to the at least one LED chip of the plurality of LED chips.

12. A light fixture or lighting apparatus according to claim 1 wherein, for each lighting device of the plurality of lighting devices, the plurality of LED chips and the at least one thermal temperature compensation circuit element are operatively configured to receive current applied between a single anode and a single cathode associated with the lighting device.

13. A light fixture or lighting apparatus according to claim 1 wherein each lighting device of the plurality of lighting devices comprises a body structure attached to or encasing at least a portion of the submount.

14. A light fixture or lighting apparatus according to claim 13 wherein each lighting device of the plurality of lighting devices comprises at least two externally accessible electrical leads arranged on or extending through the body structure.

15. A light fixture or lighting apparatus according to claim 13 wherein each lighting device of the plurality of lighting devices comprises a single reflector positioned in or on the body structure and configured to reflect light generated by each LED chip of the plurality of LED chips.

16. A light fixture or lighting apparatus according to claim 1 wherein, for each lighting device of the plurality of lighting devices, at least some LED chips of the plurality of LED chips are arranged in series.

17. A light fixture or lighting apparatus according to claim 1 wherein, for each lighting device of the plurality of lighting devices, the at least one first LED chip is arranged in parallel with the at least one second LED chip.

18. A light fixture or lighting apparatus according to claim 1 wherein, for each lighting device of the plurality of lighting devices, the at least one first LED chip comprises a blue shifted yellow emitter including a principally blue LED chip configured to stimulate emissions from a principally yellow phosphor, and the at least one

Assignees

• Van De Ven Antony Paul
• Athalye Praneet Jayant
• Harris Michael James
• Cree Inc

Inventors

• Van De Ven Antony Paul
• Athalye Praneet Jayant
• Harris Michael James

Classifications

• H05B45/56 Primary

  involving measures to prevent abnormal temperature of the LEDs · CPC title

• H05B45/28

  using temperature feedback · CPC title

• Y10T29/49117

  Conductor or circuit manufacturing · CPC title

• H05B45/24 Primary

  using electrical feedback from LEDs or from LED modules · CPC title

• H05B45/46

  having LEDs disposed in parallel lines · CPC title